This invention relates to control of a hybrid vehicle which changes over between EV running and HEV running.
JP-A-H7-75210 published by the Japanese Patent Office in 1995 discloses a hybrid vehicle provided with a generator, an engine which drives this generator, a motor which drives the vehicle, and a battery. This hybrid vehicle switches between EV running where the motor is driven only with the electric power stored in the battery without operating the engine, and HEV running where the engine is operated and at least one of the engine or the motor is used to run the vehicle.
One advantage of hybrid vehicles is EV running which is silent and pollution-free. It is desirable to perform EV in consideration of a specific place and a specific period of time. For example, if during HEV running the engine is operated when going to the office in the early morning from home or returning late at night, the noise emitted by the engine may annoy the neighborhood, but in the case of EV running, there will be little noise and the neighborhood will not be annoyed.
However, there is no reference in the literature to this way of using hybrid vehicles.
In order to use hybrid vehicles in this way, homes and offices may be provided with external charging devices which charge the battery using an external power supply, and vehicles may be provided with a map information device (for example, navigation system) which allow the present position of the vehicle to be recognized on map data. The place where the external power supply is installed may be registered as a base point on the map data in the map information device, and an EV running area centered on the base point may be registered on the map data in the map information device. The vehicle may perform EV running in the EV area when the vehicle starts from the base point after the battery is charged using the external power supply, or when the vehicle comes into the EV running area when the vehicle returns from outside the EV running area to the base point.
In this case, outside the EV running area, a target charge state may be set as a normal target charge state to perform HEV running, but the normal target charge state cannot usually be set very high. This is because the margin to the maximum charge state (the greatest charge state which can be charged) is small, and if the normal target charge state is set too high, the battery will become overcharged during regeneration. Therefore, if the vehicle enters the EV running area and switches to EV running when the charge state is maintained at the normal target charge state, the distance in which EV running is possible will be limited.
It is therefore an object of this invention to secure sufficient distance for EV running when running towards a base point from outside an EV running area, by raising the charge state of the battery when performing HEV running before reaching the EV running area.
In order to achieve above object, this invention provides a hybrid vehicle which includes a generator, an engine which drives the generator, a motor which drives the vehicle and a battery connected to the generator and motor, and performs EV running wherein the vehicle runs under the motor driven with electric power stored in the battery without operating the engine, and HEV running wherein the engine is operated and the vehicle runs under at least one of the engine and the motor, comprising an external charge device which charges the battery using an external power supply, a map information device which includes map data and recognizes the present position of the vehicle on the map data, and a controller.
The controller functions to register a point at which the external charge device is installed as a base point in the map data in the map information device, register an EV running area centered on the base point in the map data in the map information device based on a charge value of the battery, increase the charge value of the battery beforehand during HEV running before arriving at the EV running area, when the vehicle runs towards the base point from outside the EV running area, and switch to EV running when the vehicle enters the EV running area.
The details as well as other features and advantages of this invention are set forth in the remainder of the specification and are shown in the accompanying drawings.